class_docstr: Gather the dataset file from NAF dataset. Specifically for the case that
  there is a split file that contains the names of different splits. For
  example,
  
      img_001.jpg                           train: img_001.jpg
      img_002.jpg ---> split_file ---> test: img_002.jpg
      img_003.jpg                           val: img_003.jpg
  
  Args:
      split_file (str, optional): The name of the split file. Defaults to
          "data_split.json".
      temp_dir (str, optional): The directory of the temporary images.
          Defaults to "temp_images".
docstr: Returns:
      tuple(list[str], list[str]): The list of image paths and the list
      of annotation paths.
docstr_tok: ["Returns",":","tuple","(","list","[","str","]",",","list","[","str","]",")",":","The","list","of","image","paths","and","the","list","of","annotation","paths","."]
code: def __call__(self) -> Tuple[List[str], List[str]]:
      """
      Returns:
          tuple(list[str], list[str]): The list of image paths and the list
          of annotation paths.
      """
  
      split_file = osp.join(self.data_root, self.split_file)
      with open(split_file, "r") as f:
          split_data = json.load(f)
      img_list = list()
      ann_list = list()
      # Rename the key
      split_data["val"] = split_data.pop("valid")
      if not osp.exists(self.img_dir):
          os.makedirs(self.img_dir)
      current_split_data = split_data[self.split]
      for groups in current_split_data:
          for img_name in current_split_data[groups]:
              src_img = osp.join(
                  self.data_root, self.temp_dir, img_name
              )
              dst_img = osp.join(self.img_dir, img_name)
              if not osp.exists(src_img):
                  Warning(f"{src_img} does not exist!")
                  continue
              # move the image to the new path
              shutil.move(src_img, dst_img)
              ann = osp.join(
                  self.ann_dir, img_name.replace(".jpg", ".json")
              )
              img_list.append(dst_img)
              ann_list.append(ann)
      return img_list, ann_list
  
file_path: mmocr/mmocr/datasets/preparers/gatherers/naf_gatherer.py
imports: import json
  import os
  import os.path
  import shutil
  from typing import List, Tuple
  from mmocr.registry import DATA_GATHERERS
  from .base import BaseGatherer
label_desc: Use image node_id 2 for calling the NAFGatherer obj's underlying member method code with example usage: obj.__call__() and returns: img_list,  ann_list